The present invention relates to a method for estimating pressure loss of an air cleaner that is disposed upstream of a compressor of a supercharger and a device for estimating pressure loss of an air cleaner.
Japanese Utility Model Publication No. S58-15895 and Japanese Patent Application Publications 2000-97011 and 2013-36382 disclose such a method and a device for estimating such pressure loss.
According to the method and the device disclosed in Japanese Utility Model Publication No. S58-15895, loading of the air cleaner element is calculated based on the negative pressures that are electrically detected by a pressure converter at the inlet and the outlet of an air cleaner element.
In the method and the device disclosed in Japanese Patent Application Publication no. 2000-97011 an air cleaner outlet pressure sensor is mounted in an intake pipe that is provided between an air cleaner and an airflow meter, and the pressure loss of the air cleaner is calculated based on the outlet pressure of the air cleaner detected by the pressure sensor and the flow of intake air detected by the airflow meter.
In the method and the device disclosed in Japanese Patent Application Publication no. 2013-36382, an intake pressure sensor is disposed in an intake passage between the airflow sensor and an engine, and the serviceable life parameter of the air cleaner is calculated based on the intake pressure detected by the pressure sensor and the flow of intake air detected by the airflow sensor.
However, the method and the device for estimating the pressure loss disclosed in the first and second Publications need additional sensors that are not usually mounted to the engine, namely a pressure converter in the first mentioned Publication and an air cleaner outlet pressure sensor in the second mentioned Publication, respectively for calculating (estimating) the pressure loss of the air cleaner. The number of parts is increased, and the production cost is increased, accordingly. The third method and device for estimating the pressure loss is applicable only to a naturally aspirated engine and inapplicable to an engine having a supercharger that includes a compressor disposed in the intake passage between the air cleaner and the engine.
The present invention, which has been made in light of the above described problems, is directed to providing a method that can estimate pressure loss of an air cleaner that is disposed in an intake passage of an engine having a supercharger without increasing the number of parts.